Loop-spreader mechanism for chainstitch sewing machines



F. F. ZEIER LOOP-SPREADER MECHANISM FOR CHAIN-STITCH SEWING MACHINESSept 13,, $949.

' 4- Sheets-Sheet 1 Filed March 4, 1947 llll Pl [/VVE/Vfflfi. FrederickE Z6229)" ATTORNEY:

WITNESS.

J fifAza u 1949- F. F. ZEIER LOOP-SPREADER MECHANISM FOR CHAIN-STITCHSEWING MACHINES Filed. March 4, 1947 4Sheets-Sheet 2 I [NVENTflRfiedem'ok F Zez'er 14 7 T NESS'.

JM afiszczm I HTTORNEY Sept. 13, 149. F. F. ZEIER 2,482,079

' LOOP-SPREADER MECHANISM FOR CHAIN-STITCH SEWING MACHINES Filed March4, 1947 4 Shegts-Sheet 3 I HIIIH j/ 43 11 [/VVENTOZZ.

ATTORNEY Sept. 13, 1949. F. F. ZEIER LOOP-SPREADER MECHANISM FOR CRAIN-STITCH SEWING MACHINES 4 Sheets-Sheet 4 Filed March 4, 1947 a3 a5a? as f/VVENTUR Fi'ederzbk F Z9 zler WIT/V555:

ATTORNEX Patented Sept. 13, 1949 LOOP-SPREADER MECHANISM FOR CHAINSTITCH SEWING MACHINES Frederick F. Zeier, Stratfield,

The Singer Manufacturing Conn., assignor to Company, Elizabeth, N. J., acorporation of New Jersey Application March 4, 1947, Serial No. 732,184

6 Claims.

This invention relates to sewing machines and more particularly to thoseof the two-thread chain-stitch type employing a thread-carrying looper,and the invention has for an object to provide an improvedloop-spreading mechanism for engaging and spreading one limb of thelooperthread-loop to form with the needle-thread-loop which is about thelooper the usual threadtriangle for entrance by the descending needle informing the succeeding stitch.

Another object of the present invention is to provide a loop-spreaderactuating mechanism having the component parts thereof so arranged thata minimum of effort is required to operate the mechanism, the parts canbe readily assembled, manufacturing tolerances can be reasonably large,and necessary repair including the replacement of parts can beaccomplished without excessive disassembly.

A further object of the present invention is to provide a loop-spreadingmechanism in which the thread-engaging element may be universallyadjusted in order to effect a very satisfactory timing of thethread-engagin element with the other stitch-forming devices.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attaincd thereby will bereadily understood by those skilled in the art.

In the drawings,

Fig. 1 is a, front side elevational view, with a portion of the bed andcloth-plate in section, of a sewing machine embodying the presentinvention.

Fig. 2 is an enlarged top plan view of a portion of the machine-bed; thecloth-plate and the throat-plate having been removed to show moreclrarly the mechanisms within the bed.

Fig. 3 is a transverse vertical sectional view taken substantially alongthe line 3-3, Fig. 2, showing the eccentric drive for the spreadermechanism and the anti-friction bearing interpoed between the peripheryof the actuating eccentric and the pitman strap embracing saideccentric.

Fig. 4 represents a longitudinal vertical sectional view takensubstantially along the line 4--4, Fig. 2.

Fig. 5 represents a longitudinal vertical sec- 2 tional view takensubstantially along the line 5---5, Fig. 2.

Fig. 6 represents a transverse vertical sectional view takensubstantially along the line 6-6, Fig. 2.

Fig. 7 is a. fragmentary top plan view of the looper and spreader,illustrating the looper just entering the needle-thread-loop during theloopseizing stroke of the looper.

Fig. 8 is a right side elevational view, partly in section, of theelements shown in Fig. 7.

Fig. 9 is a view similar to Fig. '7, but showing the looper at the endof its loop-seizing stroke and the spreader engaging one limb of thelooperthread-loop preparatory to distending the same for entrance by theneedle on its next work-penetrating stroke.

Fig. 10 is a, right side elevational view, partly in section, of theelements shown in Fig. 9.

Fig. 11 is a view similar to Fig. 9, but showing the looper retractingto shed the needle-threadloop and the looper-thread-loop fully distendedby the spreader. v

Fig. 12 is a right side elevational view, partly in section, of theelements shown. in Fig. 11.

Fig. 13 is a fragmentary front ide elevational view of the sewin machinebed, showin a modification of the spreader-carrying arm adapted for useon a wide gauge machine. 7

Fig. 14 is a top plan view, with the cloth-plate andthroat-plate-removed, of that portion of the sewing machine bed shown inFig. 13.

Fig. 15 represents an enlarged vertical sectional view takensubstantially along the line I 5-l 5, Fig. 14. r 7

Referring more in detail to the drawings, the invention is shown asembodied in a sewing machine comprising a frame includin a bed 20 fromone end of which rises a standard 2| of an overhanging bracket-armterminating in a head 22. J ournaled in the head 22 for endwisereciprocatory and laterallyvibratory movements is a needle-bar 23carrying at its lower end a needleclamp 24 in which is fastened a pairof eyepointed threadecarrying needles 25. The needles 25 are adapted topenetrate work sustained on the work-support by a common form ofpresserfoot 26, which work-support includes a throatplate 21 andcloth-plates 28 and 29. The work is fed through the machine by means ofthe vibratory needles 25 and the cooperating feeddog 30 supported on afeed-bar 3| which derives its usual feeding motions from mechanismsubstantially similar to that forming the subject of my prior Patent No.2,292,258, issued August 4, 1942.

Cooperating with the threaded needles in forming two-threadchain-stitches are the thread-carrying loopers 32 supported foroscillation in a vertical plane parallel to the line of feed in alooper-carrier: 33 mo unted'on a fixed fulcrurn-shaft- 3 isu pported atopposite ends in bushings 34 located in the transverse partitions 35 and35 of the bed 23. The looper-carrier 33 is actuated through a rock-lever31 and link 38 from a, crank 39 mounted on the end of a rotary main orbed-shaft 4E] journaled in suitable bearings H and 52 (Fig. 1) providedin the bed 23. It will be understood that the loopers 32 have only'loopseizing and loop-shedding strokes and that these two motions arecoordinated with the reciprocatory and vibratory feeding movements ofthe needles 25 to effect stitch;formation.

To assist in proper stitch-formation, each of the two-motion loopers 32has cooperating there- I with a spreader-finger 43 (Fig. 2) which isadapted to engage and distend one limb of the looperthread-loop to formthe usual thread-triangle with the previous needle-thread-loop forentrance by the descending needle. In one embodimerit of the inventionasapplied to a narrow gauge machine (needles set relatively close toeach other), the spread-ers 43 are preferably rigidly fastened to a flatcarrier or arm 54 formed with a shank 45 Theshank 45 is slotted, as at56, through which extends a clamp-screw 41 threaded into a carrier-armholder or block 48 secured by set-screws 49 on the forward end of anendwise reciprocatory actuating or spreadersupporting bar 50. Adjustmentof the spreader fingers 43 vertically and horizontally in a directiontoward or away from the loopers 32 is accomplished by looseningtheset-screws 49 and turning or shifting th'e block 48 on thespreadersupporting bar 50, while adjustment of the spreader-fingers in asubstantially horizontal direction parallel with the lineof fee-d isaccomplished by backing off the clamp-screw 41 and shifting the carrierifrelative to the block 58. The block 48 is formed with a tongue 5|adapted to project into a groove52 provided in the shank of the carrierMQlimiting shifting of the carrier 55 relative to the'block 48 in aright line.

The spreader-supporting bar 59 is journaled for endwise movement in thespaced bearings 53 and i 54 (Fig. 2) of a bearing-bracket 55 detachablysecured on a supporting lug 56 cast integral with the front wall 5'! andtransverse partition 36 of r the bed 20, the screws58 and. locating pins59 serving to fasten thebracket 55 in its alined position. The rearwardend of the spreader-supporting bar 55 is preferably formed as a yoke 60I in the limbs of which is freely journaled a horizontally disposedconnector-pin 5| apertured,normal to its longitudinal axis, to slidinglyreceive the upwardly extending cylindrical lever-pin 52 of a drivingrock-arm 63. The rock-arm 63 is fastened on a transversespreader-driving rock-shaft 54 j ournaled at its opposite endspreferably in needlebearings fiiipressed into the side-walls of the bed20, as clearly shown in Fig. 2. The spreader-driving shaft 54 isrestrained against endwise shifting in its bearings 55 by two collars 56clamped on the shaft 6 1. The'means for rocking the spreaderdrivingshaft 64 comprises a horizontal rock-arm (Fig. 4) having a cylindricalbody 61 provided with a shank 68 threaded into the spreader-drivingshaft 54, a lock-nut 69 serving to prevent d accidental unthreading ofsaid rock-arm, Slidingly embracing the cylindrical body 61 of therock-arm is a sleeve-ball Ill seated in a socket H formed in the splitupper end of an actuating pitman 12. The lower end of the pitman 12embraces a needle-bearing l3 fitted on an actuating eccentric ll securedby set-screws 15 on the rotary bed-shaft 45. Disposed on opposite sidesof the pitman T2 are two thrust-washers 15; the pitman l2,needle-bearing 13 and thrust-washers 15 being retained on the actuatingeccentric M by a' flan'geill secured against the face of the eccentric Mby screws 18 and locked on the rotary bed-shaft 40 by the set-screws 19.To minimize vibration during high speed operation of the mechanism, theeccentric I4 is formed with a weigh-ted section 8ll and the flange 11 isformed with a similar weighted section 8|, the two sections and 8| beingdisposed diametrically opposite the point of maximum eccentricity of theeccentric 15. To further assist in balancing the spreaderfrnechanism,the driving rock-arm 63 is formed with a. depending counterbalance 82 v(Figs. 1 and 3). The actuating'eccentric 14 is timed so that thespreader-finger 53 is reciprocated crosswise of the linev of seam'formationat the proper time to spread the thread leading from thelooper-eye to form the usual thread triangle with the previousneedle-loop which is about the blade of the looper for proper entranceby the descending needle. The functioning of the spreader is illustrat din Figs. 7 to. 12, inclusive. In Figs. '7

.. and 8, the needle 25, after reaching the lowermost pointof itsstroke, has begun its ascending stroke and has castout a thread-loop NTwhich is just being entered by the beak of the looper 32. During thispart of the stitch-forming cycle, ;the spreader 53 does not perform anyuseful function; Figs. 9 and 10 disclose the looper, at the end of itsloop-seizing stroke and the needle 25 at the highest point of itsstroke. It will be seen that the spreader 43'has engaged a limb of the"looper-thread LT and ispreparing to carrying said limb to a positionfurther to the right. Figs. 11 and 12 disclose the looper 32 retractingto shed the needle-thread-loop NT, the needle 25 descend- O ing toenter'the thread triangle and the spreader 53 at the endofits-loop-distending stroke. From the above, it will be understood thatthe spreaderfinger- 43 engages and spreads one limb of the looper threadso that the needle 25 on its descending stroke will unerringly enter thespread thread-triangle, regardless of the fact that the needIe apertu'reis not stationary but is formed in the feed-dog 30'and shifts back andforth in the'line'of feed.

Figs. 1, 2, 5 and 6 are illustrative of a spreader mechanism as appliedto a narrow gauge sewing machine, i. e. one in which the needles andloopers are relatively closely spaced. Figs. 13 and 14 disclose amodification'of the spreader mechacnism which-is adapted for wide gaugesewing machines. Referring to these two figures it will be observedth'attheloopers 32 are widely spaced and are supported-by'a'looper-carrier 83 journaled for oscillation on'a fixed fulcrum-shaft34 supported at opposite endsin the bushings 34' located inthetransverse partitions 35 and 36 of the bed 25. The looper-carrier 83 isoscillated on the fulcrum-shaft 34 by the'same means hereinbeforedescribed in connectionwith the loopercarrier33. Cooperating with thewidely spaced loopers 32 are the spreader-fingers 84 (Fig. 14)preferably integral with a carrying-bar 85. The carrying-bar 85preferably has a rectangular cross-section andis supported adjacent itsopposite ends for'endwise reciprocation against the under side of thethroat-plate 2'! by two slotted bearing-blocks or guides 86, each of thebearingblocks being provided with elongated holes 81 through whichextend screws 88 threaded into the throat-plate 21. The elongated holes8'! provide for limited adjustment of the spreader-fingers 84 in a planeparallel to the under surface of the throat-plate 21. The spreadercarrying-bar 85 is reciprocated endwise by the actuating bar 55 and themeans employed for connecting said carrying-bar 85 to said actuating bar50 preferably comprises a connector-head 89 secured on the outer end ofthe actuating bar 50 by the setscrews 90 affording limited adjustment ofsaid head lengthwise of said actuating bar 59. The other end of theconnector-head 89 is formed with a channel 9! opening into the upperface of the connector-head, into which open topped channel projects ablock 92 depending from the right hand end portion of the carrying-bar85. The blockand-channel connection with the actuating bar 50facilitates removal of the throat-plate 21 and spreader-fingers 84 as aunit from the machine cloth-plate 28. The block-and-channel connectionalso accommodates whatever misalinement which may exist between thecarrying-bar 85 and the actuating-bar 50.

From the foregoing, it will be understood that I have devised a spreaderoperating mechanism having the component parts thereof interconnected ina manner to eliminate binding in the event the parts are slightlymisalined. In fact, by virtue of the universal connections between thevarious elements of the operating mechanism, manufacturing tolerances asfar as alinement is concerned may be large and therefore easilyobtainable. The presence of the detachable bearing-bracket 55 isadvantageous owing to the fact that machining of the bed 20 issimplified and the final assembly of the spreader operating mechanism isfacilitated. The universal adjustment of the spreader-fingers relativeto the loopers permits the accurate timing of the spreader-fingers withrespect to the movements of the loopers, resulting in a perfectcooperation between said spreader-fingers and loopers.

Having thus set forth the nature of the invention, what I claim hereinis:

1. In a sewing machine having a frame including a bed, the combinationwith a thread-carrying reciprocatory needle, of complementalstitchforming mechanism including a thread-carrying looper, means forimparting loop-seizing and loopshedding movements to said looper, aloopspreader, means for operating said loop-spreader including anactuating bar provided with a connector-pin, a bracket detachablysecured to said bed and providing a bearing for said actuating bar, arock-shaft, means for operating said rockshaft, and means connectingsaid rock-shaft to said actuating bar including a rock-arm fast on saidrock-shaft and having a lever-portion thereof slidingly disposed in saidconnector-pin.

2. In a sewing machine having a frame including a bed, the combinationwith a thread-carrying reciprocatory needle, of complementalstitchforming mechanism including a thread-carrying looper, means forimparting loop-seizing and loop-shedding movements to said looper, aloopspreader movable transversely of the movements j 6 of said looper,an endwise movable loop-spreader actuating bar provided with aconnector-pin, a carrier for said loop-spreader adjustably secured onsaid actuating bar, a bracket providing a bearing for said actuating bardetachably secured to said bed, a rock-shaft, means for operating saidrock-shaft, and means connecting said rock-shaft to said actuating barincluding a rock-arm secured on said rock-shaft and having alever-portion thereof slidingly disposed in said connector-pin.

3. In a sewing machine having a frame including a bed, the combinationwith a threadcarrying reciprocatory needle, of complementalstitch-forming mechanism including a threadcarrying-looper, means forimparting loop-seizing and loop-shedding movements to said looper, aloop-spreader, an actuatin bar supporting said loop-spreader and endwisemovable in a direction substantially normal to the loop-seizing andloop-shedding movements of said looper, a rockshaft journaled in saidbed transversely of said actuating bar, a rotary shaft journaled in saidbed, means including a universal connection for operatively connectingsaid rock-shaft to said rotary shaft, and means including a seconduniversal connection for connecting said actuating bar to saidrock-shaft.

4. In a sewing machine having a frame including a bed, the combinationwith a thread-carrying endwise movable needle, of complementalstitch-forming mechanism including a threadcarrying looper, means forimparting loop-seizing and loop-sheddin movements to said looper, aloop-spreader, an actuating bar endwise movable in a directionsubstantially normal to theloop-seizing and loop-shedding movements ofsaid looper, a holder mounted on said actuating bar, a carrier for said10op-spreader adjustably secured to said holder, a rock-shaft journaledin 3 said bed and disposed transversely of said actuating bar, means foroperating said rock-shaft, and means operatively connecting saidactuating bar to said rock-shaft, said means having capacity toaccommodate slight misalinem'ent between said actuating bar and saidrock-shaft.

5. In a sewing machine having a frame including a bed, the combinationwith a thread-carrying endwise movable needle, of complementalstitch-forming mechanism includin a threadcarryin looper, means formoving said looper so that the beak thereof travels in a vertical plane,a loop-spreader, a bracket detachably secured to said bed, an actuatingbar journaled in said bracket for reciprocation in a directionsubstantially normal to the plane of movement of said looper-beak, meansadjustably securing said spreader to one end of said actuating bar, arockshaft journaled in said bed and disposed substantially parallel withthe plane of movement of said looper-beak, means including a universalconnection operatively connecting said rock-shaft with said actuatingbar, a rotary main-shaft journaled in said bed and disposedsubstantially parallel to said actuating bar, and means connecting saidrock-shaft to said rotary main-shaft.

6. In a sewing machine having a frame including a bed and a removablethroatplate, the combination with an endwise reciprocatorythreadcarrying needle, of complementary stitch-forming mechanismincluding a thread-carrying looper, means for imparting loop-seizing andloop-shedding movements to said looper, a loopspreader, a carrying-barsupported for endwise sliding movement on the under side of said2,48230791 7 8*. throat-plate, a blockdepending from said carry- YREFERENCES CITED ing-b'ar, an actuating bar 'journaled for endwisereciprocation in said bed, means for reciprocating said actuating bar,and a connector-head The following refefences are of record in the fileof this patent:

fixed on said actuating bar having an open topped 5 UNITED STATESPATENTS channel into which projects the block depending Number NamevDate fmm Sam carrymg'bar- 1,443,084 Mofiatt et a1. Jan. 23, 19231,995,078 Rubel Mar. 19, 1935 FREDERICK ZEIER- 2,312,858 Zeier Mar. 2,1943

